Charcoal kiln



: 18. 9 G. JOHN 2,956,933

- CHARCOAL KILN Filed April 29, 1957 4 Sheets-Sheet 1 INVENTOR F |27 32 32 32 GERALD JOLIN ATTORNEYS G. JOLlN CHARCOAL KILN Oct. 18, 1960 4 Sheets-Sheet 2 Filed April 29. 1957 FIGJO.

INVENTOR GERALD JOL! N ATTORNEYS G. JOLIN CHARCOAL KILN Oct. 18, 1960 4 Sheets-Sheet 3 Filed April 29 1957 INVENTOR GERALD JOLIN MW; 94%, v t

Oct. 18, 1960 G. JOLIN 2,956,933 CHARCOAL KILN Filed April 29, 1957 4 Sheets-Sheet 4 INVENTOR GERALD JOLIN ATTORNEYS CHARCOAL KILN Gerald Jolin, Waupaca, Wis, assignor to Berwind Fuel Company, Chicago, 111., a corporation of Delaware Filed Apr. 29, 1957, Ser. o. 655,720

2 Claims. (Cl. 202-6) This invention relates to a method and apparatus for producing charcoal economically and rapidly from timber in its green state and wood in various stages of dryness, as well as sawdust, wood shavings, pulps, pulp residues,

etc.

The formation of the charcoal preferably takes place in a metal kiln, e.g., of the Quonset type of building, which will have the important advantage of allowing rapid cooling of the charcoal and kiln upon the completion of the coaling operation.

The primary object of the invention is to provide a method of making charcoal which will assure the maintenance of adequate temperature conditions in the kiln for producing the charcoal, and also permit the charcoal and the kiln to be quickly cooled after the coaling has been completed, so that the charcoal may be removed and a new charge of wood supplied to the kiln with a minimum of delay in each operation.

Another object of this invention is to provide a kiln which will be strudy in construction, and which will withstand the high temperatures necessarily employed in making the charcoal and, at the same time, the kiln will be capable of ready manipulation for the purposes of loading the raw material and removing the finished charcoal.

The kiln shown in the appended drawings is of the semi-cylindrical Quonset type made of 14 gauge hot rolled steel, but other shapes may be employed, although they are not preferred.

Referring to the drawings:

Figure 1 is a perspective view of the kiln;

Figure 2 is a sectional view on the line 22 of Figure 1;

Figure 3 is a sectional view on the line 3-3 of Figure 2;

'Figure 4 is a perspective view of the kiln looking at the bottom and showing one modification of the bottom structure, the kiln being available for loading in this reverse position and then being turned to the position shown in Figure 1 for coaling;

Figure 5 is a perspective view of another type of bottom and illustrating the manner in which the kiln may be raised from a bottom, as well as indicating wedge members which are employed to elevate the kiln to assure an excess supply of air to promote initial combustion of a portion of the wood;

Figure 5a is a sectional view showing the stringers tapering in size vertically from the center stringer of the kiln toward each end thereof, whereby the center stringer will be vertically the thickest and the end stringers adjacent each end of the kiln will be the thinnest;

Figure 5b is an elevation of an individual stringer modified to have the upper supporting surface thereof taper transversely toward the sides of the kiln so that the thicker portion of each stringer is in the center and the stringer has portions inclining toward the ends thereof;

Figure 6 is an end view of the construction shown in Figure 5;

Patented Oct; 18, 1950' Figures 4 and 5, and closed ends 12, as shown in Figures 1, 4 and 5.

A bottom 13 is made in metal sections 14 joined transversely by hooked joints 15 so that any section which wears may be readily replaced, as will be understood from reference to Figure 2.

The bottom is detachably connected to the kiln body 10 by suitable rods 16 extending transversely across the bottom beneath the same, as shown in Figure 4, and held in oposed openings 17 spaced at the lower edges of the longitudinal sides or walls 18 of the kiln.

Thus, the wood 19 may be laid in the Quonset while the latter is turned up, as shown in Figure 4, whereupon the bottom 13 is attached, as shown in Figure 4 and, thereafter the kiln is righted for burning, as shown in Figure 5, by means of the cable 20 attached to a suitable winch or other means.

The openings 21, as shown in Figures 2 and 4, allow oil-soaked rags or other combustible material, to be inserted through the end walls 12 so that the charge will be initially consumed in the area defined by the dash lines AB longitudinally of the kiln, as shown in Figure 3.

The charge in the central area AB is ignited, as described, and the vents or openings 21- 22 in the ends and sides of the kiln, as well as the opening 23 in the top of the kiln, all as shown in Figures 1, 4 and 5, create a suitable draft to promote rapid complete combustion. Indications are taken from time to time to show when the charge in the central area AB has been consumed and the burning of this charge provides the heat necessary to produce coal-ing of the remainder of the charge in the kiln.

The air stream or draft created in the kiln travels in the channels created by the spaced angle irons 24 which, as shown in Figures 2 and 3, provide transverse passages from the bottom of the kiln in each side to the top thereof and the angle irons 24' provide channels directly opening into the top outlet 23, as shown in Figures 2 and 3.

When combustion of this section AB of the charge is completed, the fuel charge openings 21 are sealed by' caps 25, as shown in Figure 1, and covered with sand to provide a further seal.

iThen, suitable pipes 2 6 upstanding, as shown in Figure 1, are connected to the vent openings 22 at one side of the kiln and the top vent 23 is closed wholly or partially.

Since the kiln has been brought to coaling temperature by the burning of the wood in area AB, the effect of the pipes or chimneys is to create a draft toward that side of the kiln to coal the charge in section D, as shown in Figure 3, and when indications show this is completed, the pipes are transferred to the other side of the kiln, as shown in dash lines in Figure 1, and coaling of section C is completed.

The pipes 26 are connected to the vents 22, as shown in Figure 1, by a friction fit of the elbow 27 over the spud or outlet 28, which defines the outlet 22 in each instance, as shown in Figures 1 and 3.

When indications show coaling is completed, in the sections C and D longitudinally of the kiln, the pipes 26 are removed and the spuds 28 are capped, as shown in Figure 3 at 29, whereupon all the capped vents 21 and 22 are covered with sand while the kiln and contents are allowed to cool. This is facilitated by the metal structure of the Quonset 10.

Instead of filling or loading the Quonse in its up turned position, as shown in Figure 4, the plate or'bottom 13 is held between vertical stakes 30 fixed in the ground, as shown in Figure 5, and the Quonset structure then disposed over the bottom after the wood has been piled up, as shown in dotted lines. In Figure S'; instead of a continuous metal bottom, as shown in Figure 4, the bottom is provided by transversely spaced metal or wood stringers 31, as shown, or the stringers are superposed on the metal bottom 13, shown in'Figures 3, 4 and 5a, where, for purposes of illustration, the metal" plate is indicated at 13d.

Whether the bottom 13 is used as inFigure 4 or in Figure 5, or modified as just described, with the transverse stringers disposed on the metal bottom or simply the stakes 30 are fixed in the ground with the wood 19 piled between the same, and the Quonset then applied over the built-up log pile, with each of these modified procedures from that used in connection with Figure 4, in starting, the Quonset is held above the ground or bottom 13 on all sides and ends by wedges 32, as shown in Figure 5, so that rapid combustion in zone AB is assured-by the air so entering beneath the kiln, as well as through the openings 2l-22 and the top outlet 23. When the zone A--B has been sufiiciently combusted and the temperature in the kiln reaches the desired coal ing temperature, the wedges are removed and the lower edge of the kiln is sealed with the plate, or the stringers, or the ground, by sand piled around the same and the end caps 25; Thereafter, the operation proceeds as described above with adjustment of the opening 23 in the top by shifting the closure 33 thereof to completely or partly close the vent 23. This closure 33 is slidably mounted in the top in guides 33, as shown in Figure l, but may be made adjustable in any desired manner.

The operation is continued as previously described by transferring the chimneys or draft flues 26, as indicated in Figure l, to promote coaling of the wood on both sides of the zone AB, as described above.

The inwardly projecting, inwardly disposed and transversely spaced angle irons 24-24 provide ducts or channels, as above related, for positively circulating the air and combustion gases, and also aid in drying, out the wood in the zones C and D prior to actual coaling of the same. These angle irons protect the inner metal sides or surface of the kiln when the cover is lowered over a charge or the loaded kiln is rolled or rocked, for instance as would be the case in Figure 4.

The cover 33 over the vent 23 is adjustable, as stated, so as to control, to some extent, the air and gas flow and the draft over the wood in the chamber 10. Referring to Figures 8 and 9, all of the angle irons 24 -24' form channels which extend from the bottom of the kiln and terminate, i.e., communicate and directly open into the vent or top opening 23, which is employed to control the gas and air flow. The location of the inwardly extending channel or duct forming angle irons is shown in Figure 8, and in Figure 9a skeleton angle iron frame is illustrated for purposes of clarification.

In Figure 7, the ends 12 of any of the kilnshereindescribed are shown as beingreinforced by similar angle irons 24 arranged to exert a deflective action on the gases passing through or formed in the chamber 10, as well as to reinforce the ends.

The preheating of the wood in Zones C and D; during combustion of the wood in the area A B by reason of. the gas flow in the chamber, facilitates and speeds, up the coaling of the wood in these zones, and it is noted. that steam and combustion products are givenolf through the end and side openings 21-22 anrltop'vent 23 during combustion. in the central zone .A--B.-

When coaling is completed in.zones C and D, thiscan be ascertained by introducing a rod through one or more openings 22, whereby such prodding will indicate the absence of large particles and/or solids of substantial size.

The angle irons 2424 help to keep the Quonset in shape and are tensioned or bowed to engage the inner surface of the Quonset wall to which they are welded at their ends, i.e., to the top and bottom of the kiln.

The Quonset has suitable hand holes or handles, not shown, whereby it may be lifted or turned upside down and returnedto normal position, as desired.

The temperature of the kiln is controlled and when the combustion in zone AB is completed, this is ascertained by applying drops of water to the outer surface of the kiln about the vent 23. If they run off, the combustion is completed, but if there is sputtering or sticking, then the interior temperature is not hot enough and the buming in zone AB is continued. Also, the complete or desired burning in the central area AB is shown by reduction of pressure in the vents 22, and the decrease in smoke and products of combustion passing out through these outlets and the vent 23.

The satisfactoryv formation of charcoal is indicated by the emission of thick yellow and white fumes. When thin blue smoke appears, ashes are being made, and when black smoke shows, the charcoal is being burned. The volume and color of gases emitting from the stacks 26 show the progress of the operation of making charcoal. Thus, an operator, by observing the color and texture of the gas emitting from the vent 23- and stacks 26, can determine the progress of the burning in the central area AB, and the formation of the charcoal in the distillation areas C and D.

The vent 25 by its closure 33 is controlled to vary the gas flow through the chamber, as described, and, hence, the amount of air and rate of combustion and distillation. The vent may be wholly closed or only partly closed, from time to time, as coaling proceeds.

Thus, the temperature in the chamber during initial coaling is between 800 F. and 900 F. but this will depend upon the character of the products in the zone AB as well as the character of the material from which the charcoal is being formed. The temperature of about 800 F. to 900 F. is considered preferable for most purposes, but it can be appreciated that lower temperatures created in the kiln or chamber 10 may be satisfactory to produce coaling of certain types of wood, while higher temperatures may be required, on some cases, with other types of products which are to be coaled.

When the coaling is completed, the vents are all sealed, as described, and the metal wall of the Quonset" assures quick cooling.

Not only is the operation of forming the charcoal rapidly completed for this reason, but, further, objectionable burning of the charcoal is thus arrested.

Kilns according to this invention range in size from 55 gallon drumysize to 144 cubic foot size.

In connection with the ports 21 and 22, and the closing of the same, stamped 20 gauge steel covers or caps are provided in 4 inch diameter and A3 inch rim to cover ports for cooling, i.e., quenching. Together with sand piled against the slanting sides of the kiln, they form adequate gas seal for quenching.

The top opening 23 of the kiln is preferably formed by a square of 1 /2 x 1 /2 inch angle with web 23' turned in to form a seat for a flat steel cover 33.

This frame, when cover 33 is so inserted, forms a 1 /2 inch depth box, into which sand is poured to make a sufficient gas seal for cooling and quenching during coaling.

Alternatively, the kiln is loaded with its open side up, as shown in Figure. 4. Steel (24 gauge hot rolled) covers, i.e., bottoms 13,.with four convenient hand holds are laid on top of the pile of wood 19 and rods 11 are inserted to keep bellying of the charge in control while turning the kiln with the chain or cable wrapper 20.

When the kiln is turned on its flat side for firing, as in Figure l, the rods 16 are pulled out for use on the next kiln in a battery of kilns, by inserting a modified type of common hay-bale hook in a ring on one end of each rod (not shown) and applying pressure to pull out the rods.

On kilns to be loaded with short waste, five inch holes are drilled on each side at base in 1 /2 x 1 /2 inch angle iron frame crosswise of the kiln and opposite each other. Into these holes are inserted 7 /2 foot [2 inch diameter rods with ringed ends, not shown, for removal handle, and with spaced cotter pin holes on beveled ends.

As described, at each end 12 of the kiln, two 4 inch collared holes 21, for firing, are placed in the center 1 /2 inches from ground level. The collars welded at these ports 21 are designed to accommodate common stove pipe elbows and pipe sections, if desired.

A practical kiln consists of a 7 foot x 9 foot frame, a 3 /2 foot radius half shell 10 of 14 gauge hot rolled steel, having radial ribs 24-24 on each side of the kiln, extending from a central top opening 23 in fan-fashion, as shown in Figures 8 and 9, to the spaces between six 4 inch air ports 22. These 6 air ports 22 are spaced equally, beginning 10 inches from each end of the kiln base, 1 /2 inches up from ground level. They are 4 inches in diameter and fitted with 1 inch steel collars extending outward perpendicularly to the shell or skin.

Most all native wood species were successfully coaled in kilns as described herein, in varying moisture contents, stick diameters, and firing temperatures.

The kiln described herein is useful also on sawdust and paper-mill bark waste, the latter both hogged and un hogged. (Hog being a hammer or other type mill used to reduce waste to homogeneous particle size.)

In practical operation, the kiln 10 is lowered over a 1 cord stack of green wood and rests on chocks or wedegs 32 which hold it an inch or two off the surface of the ground, and all vents, including the large top vent 23, are open to allow free passage of air. The charge is ignited by introducing 2 quarts of combustible mixture consisting of 80% crankcase oil and 20% kerosene through the center vents 21 and stuifing an oil-soaked rag into each end vent 21, the rags being then touched off with a match. The charge is allowed to burn freely for about 1 hour. At the end of the hour, combustion in zone A--B is completed and the chocks are withdrawn and the kiln rests solidly on the ground. Sand is banked all around the bottom edge to seal the kiln l0. Vents 2 on one side then have 6 foot lengths of 4 inch diameter stove pipe 26 attached, as shown, to coal the charge. The large center vent is covered, partly or wholly, with the lid 33 and sealed with sand. The kiln, if wholly closed in this manner, sits for 4 hours, sucking air through the open vents 22 of one side and the ends 21 and discharging gases through pipe 26. At the end of 4 hours, the pipes 26 are shifted to the vents 22 on the opposite side and the kiln is left for 3 hours. At the end of 3 hours, coaling is completed in sections C and D. The pipes 26 are then removed and all vent holes and top opening 23 are plugged, and the kiln is allowed to cool for approximately 7 hours. When the cool kiln is removed, the charcoal yield is approximately 400700 pounds from about cord of the wood. Of course, the yield will depend on species and condition being coaled.

Kilns in all stages of the operations described above were observed. The quality of the charcoal was very satisfactory. An analysis showed:

Moisture 5.0

Volatile 11.3

Ash 1.8

Fixed carbon 86.9

In the example just referred to above, the temperature in the kiln, after the charge in the central area AB was 6 completely combusted, was 800 F., whereupon the stacks 26 were applied, as described above, and the entire kiln, after coaling of the charges in the areas CD, was sealed with sand and allowed to cool.

The temperatures maintained within the kiln are of course dependent upon the character of the wood being coaled and this will necessarily vary, for example, depending upon the dryness of the wood as well as its make-up, since some woods contain moreresins and cellulose materials than do others.

Referring to Figure 2, it will be noted that the transversely extending joints between the bottom sections 13 may be in the form of a continuous interfolded metal connection, or they may be connected in any desired manner which will allow the sections to be independently attached to one another and similarly detached. The bottom so formed may be longitudinally rigid like a continuous plate, or the joints may allow the sections to flex with respect to one another.

Without being limited to a theory of operation, it is believed that the combustion of the central charge in the zone AB, providing the necessary coaling temperature, also forms a void extending longitudinally of the kiln. Thus, when the piles 26 are attached to one side or the other of the kiln, air will be drawn through the opposite corresponding set of openings 22 and will circulate in the kiln not only in the void created by combustion of the wood in the zone AB, but through the channels created by the angle irons as well, and discharged through the pipes 26, which extend above the top of the kiln a sufficient distance to form an adequate flue or chimney to create a desirable draft. It is understood, of course, that the combustion of the wood or other material being distilled in the zone AB provides the necessary temperature for distilling the material in the zones C and D and forming the charcoal.

Also, it is, of course, understood that while an excess of air is supplied to promote combustion of the wood in the central area AB, after this has been completed, the air which is introduced to the kiln for coaling, is supplied in an amount to prevent any substantial burning of the remaining charge on each side of the central area.

In connection with the stringers 31, whether these are used without the metal bottom or superposed upon the same, as described above, they preferably taper in size vertically from the center stringer of the kiln toward each end thereof, as shown in Figure 5a. That is to say, the center stringer 31a shown in Figure 5a will be vertically the thickest while the end strings 31b adjacent each end 12 of the kiln will preferably to the thinnest. Also, in some cases, it may be desirable to have the upper surfaces of the stringers themselves taper transversely so that the flat thicker portion 31c of each stringer is in the center and inclined portions 31d extend or taper toward the sides of the kiln, e.g., the sections C--D as shown in Figure 5 11.

Referring to Figure 10, it is sometimes desirable in initiating the coaling operation to raise one side of the kiln higher than another and this is accomplished by inserting a block 50 under one side of the kiln and when steam no longer issues in substantial vlolume, this block can be re moved and the operation continued as described above. Sometimes this is desirable in the case of green wood so as to give a fast start and accelerate the removal of moisture, as shown by the steam issuing from the kiln. When this indication has reached a satisfactory point, it is only necessary to knock out the block 50 with a crowbar and continue the operation as described above, i.e., by allowing the kiln to be lowered over the wood by falling of its own weight or by the cable 20.

I claim:

1. A method of making charcoal from wood when using a kiln, which method comprises placing wood within the kiln, igniting wood in the central area of said kiln, creating during a first time a draft in said kiln whereby the wood in the central area ofsaid kiln is substantially completely. burned, creating during. a second'time a draft inlsaid kiln wherebythe Wood an one. side of saidcentral area of said kiln is substantially completely burned, ,re; versing the directionoflthe v draft created during said sec- 0nd time whereby during a: third time the wood on side, Opposite to'said'one side of said central area is substantially completely burned, and cooling said :chamber and the COHtClltSathGIfCOf.

2. The method of making charco aLfrom, wood .when using a kilnaas defined tin claiml wherein thez-method further includes raising thekiln; slightly: above: the normal surface for supporting: the. kiln ;during;-said; first ;time and;

sealing the kiln to said normal supporting surface during said second and third times.

References Cited in the file of this patent UNITED STATES PATENTS new. .4 

1. A METHOD OF MAKING CHARCOAL FROM WOOD WHEN USING A KILN, WHICH METHOD COMPRISES PLACING WOOD WITHIN THE KILN, IGNITING WOOD IN THE CENTRAL AREA OF SAID KILN, CREATING DURING A FIRST TIME A DRAFT IN SAID KILN WHEREBY THE WOOD IN THE CENTRAL AREA OF SAID KILN IS SUBSTANTIALLY COMPLETELY BURNED, CREATING DURING A SECOND TIME A DRAFT IN SAID KILN WHEREBY THE WOOD ON ONE SIDE OF SAID CENTRAL AREA OF SAID KILN IS SUBSTANTIALLY COMPLETELY BURNED, REVERSING THE DIRECTION OF THE DRAFT CREATED DURING SAID SECOND TIME WHEREBY DURING A THIRD TIME THE WOOD ON THE SIDE OPPOSITE TO SAID ONE SIDE OF SAID CENTRAL AREA IS SUBSTANTIALLY COMPLETELY BURNED, AND COOLING SAID CHAMBER AND THE CONTENTS THEREOF. 